Protected die-cast structure



F. BRISCOE.

PROTECTED DIE CAST STRUCTURE. APPLICATION FILED MAY 23. 1919.

Patented Mar. 15, 1921.

. UNITED STATES PATENT OFFICE.

FRANK BRISCOE, OF JACKSON, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO BRISCOE DEVICES CORPORATION, OF PONTIAC, MICHIGAN, A CORPORATION OF MICHIGAN.

PROTECTED DIE-CAST STRUCTURE.

Specification of Letters Patent.

Patented Mar. 15, 1921.

Application filed May 23, 1919. Serial No. 299,319.

To all whom it may concern 7 Be it known that I, FRANK Bnrscon, a citizen of the United States of America, residing at Jackson, in the county of Jackson and State of Michigan, have invented certain new and useful Improvements in Protected Die-Cast Structures, of which the following is a specification, reference being had therein to the accompanying drawm s.

The invention relates to constructions composed in whole or in part of die cast elements, and particularly to structures designed for use in connection with hydrocarbon fuel, such for instance as 'carbureters, inlet manifolds, etc.

It is the object of the invention to prevent the corrosion of the surfaces exposed to the oil and to obtain a more durable and permanent structure, set forth.

In the drawings I have shown my invention as applied to a carbureter, in which- Figure 1 is a longitudinal section through the carburetor;

Fig. 2 is a perspective view of some ofthe parts detached. 7

In the manufactureof die castings it is usual to employ an alloy containing a number of different metals. As is well understood, these metals do notform a chemical compound, but form a-complex agglomeration of mixed crystals or masses. Thus when exposed to an electrolyte galvanic action is set up between the different metals, resulting in local electrolysis and in destructive action on the more positive elements.

In the refining of hydrocarbon oils, such as are used for liquid fuel in internal combustion engines, thereare acids and other as hereinafter fully corrosive materials used which are seldom,

if ever, completely eliminated, and which, in connection with water generally present to a greater or less extent, will form a mild but persistent electrolyte.

When such hydrocarbon oils are brought in contact with the surface of a die casting an electrolytic action is set up, resulting in destruction of some of the elements and in hastening the corrosion of others. This corrosion often results in a carbureter for example, in deposits of oxids or other compounds on the surface in such a way as to clog up small passageways or to alter the relative dimensions of parts whose relative dimensions require to be kept constant. There is also electrolytic action set up between the surface of the die casting and other elements of the structure which may be formed of different metals, as for instance where. other parts are used in connection with die cast parts.

To avoid the corrosion and destruction of the die cast elements I have protected the exposed surfaces of such elements with a coating of a single metal. I further avoid possibility of galvanic action by using for this coating a metal which is the same or has similar electrical characteristics to the metal used in other associated parts of the structure. Thus where die cast parts are associated with parts formed of nickel or nickel alloy, the coating of the exposed surfaces of the die casting with nickel will avoid galvanic action.

ile 'my invention is applicable to various structures, I have specifically shown a carburetor, in which A is the outer casing formed of a die casting and depending leg B for the attachment of the float chamber C, indicated in dotted lines, and for also forming the fuel passage therefrom into the mixing chamber. D is a inetering device operating in the member B and formed of a different metal, and E is an air shutter pivotally mounted within the casing A, having also an operative engagement with with the member D. The member D is engaged with an adjustable screw F for controlling the discharge of liquid fuel.

After the several dies cast elements have been formed, those exposed to the hydrocarbon are provided with a surface coating of another metal. such as copper or nickel. This coating indicated bv A may be very thin but it will nevertheless completely protect the complex metal surface of the die casting from contact with any fluid which might act as an electrolyte, and therefore galvanic action is prevented. Furthermore, where the associated elements, such as the member I), are formed of metal the same having similar electrical characteristics to the coating metal, all galvanic action between these parts will beprevented.

What I claim as my invention is 1. In a structure exposed to electrolytic action, the combination with a metallic die cast part, of a coating for the exposed surface of said part formed of a single metal.

provided with a.

2. In a structure exposed to galvanic action, the combination with a metallic die cast part and an associated part of different metal, of a coating for the exposed surface of the die cast element formed of a metal the same having similar electrical characteristics to the metal of the associated part.

3. In a structure exposed to galvanic action, a metallic die cast element formed of an alloy containing zinc, and a protecting coating of a different metal.

4. In a structure exposed to electrolytic action, the combination with a metallic die cast part, of an electrolytically deposited 15 coating for the exposed surface of said part formed of a different metal.

5. In a carbureter, the combination with a I metallic die cast member, of a metallic coating for the exposed surface of said die cast 20 art. p In testimony whereof I aflix my signature.

FRANK BRISGOE/ 

